Fuel loading at India’s first prototype fast-breeder reactor (PFBR) in Kalpakkam, Tamil Nadu, is set to begin next week following the resolution of earlier technical challenges. This sodium-cooled, 500 MWe reactor, being only the second of its kind globally after Russia’s, is a thorium based reactor which uses plutonium-based mixed oxide (MOX) fuel and liquid sodium as coolant. Designed to operate for 40 years, the PFBR will breed more fuel by converting uranium-238 and thorium-232 in its blanket into fissile material, supporting India’s three-stage nuclear program that recycles spent fuel to minimize radioactive waste and harness thorium reserves. The reactor features advanced safety mechanisms, including a negative void coefficient for passive safety and multiple shutdown systems. Its commissioning marks a major step toward India’s goal of expanding nuclear power capacity to 55 GW by 2031-32, enhancing energy security and sustainable clean energy production. Fuel loading enables expected first criticality within six months, after which power output will gradually increase to full capacity. The project reflects significant indigenous efforts involving over 200 Indian industries.